In general, a fluid permeable film is used for the purpose of separation, purification, filtering, analysis, reaction, diffusion or the like of a fluid (a gas or a liquid). In particular, an anodic oxide film is available as a fluid permeable film which can be manufactured at a low cost and which has a plurality of pores.
The anodic oxide film, which is formed by anodizing a base metal, includes a porous layer having a plurality of pores formed on the surface thereof. The base metal referred to herein may be aluminum (Al), titanium (Ti), tungsten (W), zinc (Zn) or the like. However, aluminum or aluminum alloy, which is lightweight, easy to process, superior in heat conductivity and free from contamination of heavy metal, is widely used as the base metal.
As shown in FIG. 1, a fluid permeable anodic oxide film of prior art manufactured by anodizing metal is disclosed in U.S. Pat. No. 8,210,360.
In the anodic oxide film of prior art, the inner width of pores formed in the anodic oxide film falls within a range of about several nanometers to 300 nanometers. Since the inner width of pores is too small, the pores are easily clogged by extraneous materials contained in a fluid permeating through the anodic oxide film. This poses a problem in that the fluid is unable to easily permeate through the anodic oxide film.
In order to ameliorate the problem caused by the small diameter of the pores of the anodic oxide film, it is conceivable to use a method of enlarging the pores of the anodic oxide film. However, since the inner width of the pores is in an order of nanometers, it is difficult to enlarge the pores. In addition, there is a drawback in that the structural strength of the anodic oxide film is significantly reduced by the enlargement of the pores.
A fluid passing member, through which a fluid (a gas or a liquid) can pass, is used for the purpose of diffusion, separation, purification, filtering, analysis, reaction or the like of a fluid.
In general, a plurality of through-holes is formed in the fluid passing member so that a fluid can pass through the through-holes. In order for a fluid to be uniformly diffused after passing through the fluid passing member, it is preferred that the number of the through-holes is increased while reducing the inner width of the through-holes. However, difficulties are involved in reducing the inner width of the through-hole.
As an example of the fluid passing member mentioned above, there is available a diffuser (shower head) for uniformly injecting a gas toward a glass accommodated within a vacuum chamber for the manufacture of a liquid crystal display (LCD). The liquid crystal display (LCD) is a non-light-emitting element formed by filling a liquid crystal between an array substrate and a color filter substrate and configured to obtain an image effect using the characteristics of the liquid crystal. Each of the array substrate and the color filter substrate is manufactured by a process of repeatedly depositing a film on a transparent glass made of glass or the like and a process of patterning and etching the film thus deposited. When the deposition process is performed by introducing a reactant and a source material into the vacuum chamber in a gaseous state, the gas thus introduced passes through a diffuser (shower head) and is deposited on a glass mounted on an upper surface of a susceptor, thereby forming a film.
A diffuser (shower head) of prior art, which is a fluid passing member, is disclosed in Korean Patent Registration No. 0653442.
As illustrated in FIG. 8, a reaction gas introduced through an introduction part 18 passes (permeates) through a diffuser 15. The reaction gas is injected toward a glass mounted on a susceptor S.
However, there is a problem in that it is impossible to uniformly inject the reaction gas toward the glass through the holes formed in the diffuser of prior art. In order to ameliorate this problem, it is conceivable to reduce the inner width of the holes and to increase the number of holes. However, there is a limit in manufacturing the diffuser of prior art.